Influence of high growth rate on GaAs-based solar cells grown by metalorganic chemical vapor deposition

Single-junction GaAs-based solar cell structures are grown by metalorganic chemical vapor deposition system at the growth rates of 14 μm/hr and 56 μm/hr. The X-ray diffraction study reveals that the crystal quality of the structures with varying the growth rates is comparable. From the external quantum efficiency spectra, it is observed that different behaviors exist in the short wavelengths (<; 450 nm) and the long wavelengths (> 500 nm) as the growth rate increases. The short-circuit current densities of the standard and fast grown cells are comparable. However, the open-circuit voltage of the fast grown cell is lower by above 40 mV as a result of the reduced minority carrier lifetime in the base layer, which is estimated by PC1D simulation.